Conventional louver assemblies are generally constructed as single piece assemblies including a peripheral flange which engages the perimeter of a wall opening. Many such conventional louver assemblies are relatively heavy and bulky, making installation difficult, dangerous or even impossible. This is especially the case for louver assemblies weighing over one hundred pounds (for example, 4.times.8 foot louvers). During installation, such conventional louvers have to be maneuvered out of the wall opening and often must be supported by the installer who must reach out through the opening to align the louver and draw it back into the opening. This process is difficult and dangerous, especially when the wind is blowing and/or when air is moving in or out of the wall opening. After such a louver has been installed, the installer must seal the opening to prevent water and cold air from entering the building. On any floor above the first floor of the building, it is difficult (or impossible) to reach the louver and properly seal the louver flange to the building. This is due to the fact that the louver blades prevent the installer from reaching through the opening to access the exterior of the louver or the exterior building surface.
Another known louver assembly includes no outer flange and may, therefore, be installed without being passed to the outside of the building and then drawn back into the wall opening. Such a louver may slide directly into position within the wall opening from the inside of the building. However, the joint between the outside of such a flangeless louver and the wall opening often cannot be properly sealed. Thus, the connection is not air or water tight. The lack of a flange also makes it more difficult to properly align the louver within the wall opening.
Furthermore, connection between such known louvers and duct work is cumbersome. The conventional louver designs provide a one inch wide flat surface around a back exterior of the louver. The ducts are often provided with a one inch flange either on an inside or outside surface thereof, which is then attached to the louver flange using screws. With such an arrangement, achieving a permanent air tight seal is difficult and time consuming.